Problem: Stephanie ate 1 slice of pie. Luis ate 1 slice. If Stephanie ate $\dfrac{1}{3}$ of the pie, what fraction of the pie is remaining?
Solution: If 1 slice represents $\dfrac{1}{3}$ of the pie, there must have been a total of 3 slices. $\text{fraction of pie remaining} = \dfrac{\text{number of slices remaining}}{\text{number of slices total}}$ Together they ate 2 slices, which leaves 1 out of 3 slices remaining. There is $\dfrac{1}{3}$ of the pie remaining.